In a nuclear reactor, there is a danger that the nuclear fuel might get hot enough to melt and escape its containment, which would cause the release of large amounts of deadly radiation into the environment. Ordinarily reactor's are provided with water cooling ducts and other apparatus for maintaining the temperature of the fuel of the reactor, however, in the event of a failure of the cooling system, the reactor fuel will elevate the temperature to a point where the fuel will become melted into a flowing mass. This fluid flowing mass, will in turn, tend to increase its own temperature while it continues as a mass. Such a mass of molten fuel is extremely radioactive and accordingly, causes its own temperature elevation to a point where primary and secondary containments will be breached and will thereby expose the radioactive material to the environment.